GEOLOGICAL SURVEY CIRCULAR 204

FLOODS IN YOUGHIOGHENY AND KISKIMINETAS RIVER BASINS AND

FREQUENCY AND MAGNITUDE

Prepared by Water Resources Division

UNITED STATES DEPARTMENT OF THE INTERIOR Oscar L. Chapman, Secretary

GEOLOGICAL SURVEY W. E. Wrather, Director

GEOLOGICAL SURVEY CffiCULAR 204

FLOODS IN YOUGHIOGHENY AND KISKIMINETAS RIVER BASINS PENNSYLVANIA AND MARYLAND

FREQUENCY AND MAGNITUDE

Prepared by Water Resources Division

Prepared in cooperation with the Pennsylvania State Department of Forests and Waters

Washington, D. C.,1952 Free on application to the Geological Survey, Washington 25, D. C.

CONTENTS

Page Page Introduction...... 1 Gaging-station records--Continued Method...... 1 Kiskiminetas River basin--Continued Records Available...... 1 at Tunnelton, Pa .•.. 13 Flood-frequency relationships...... 3 Kiskirninetas River at Avonmore ...... 14 Analysis of flood data...... 3 Little Conemaugh River at East Plotting positions...... 3 Conemaugh...... 15 Adjustment to base periods...... 3 Blacklick Creek at Blacklick •••••.•.. 15 Test for homogeneity...... 4 at Kingston ...... 16 Median flood ratios...... 4 Loyalhanna Creek at New Alexandria •.. 16 Composite flood-frequency graphs...... 4 basin: Mean annual flood. • . . • ...... • . . . • ...... • . 9 Youghiogheny River at Ohiopyle, Pa ... 17 Computation of comparable means...... 9 Youghiogheny River at Connellsville .. 18 Mean annual flood versus drainage area. 9 Youghiogheny River at Sutersville .... 19 Application of flood data ...... 10 Casselman River at Markleton...... 20 Stage frequencies ...•••••••..•...... 11 Big Piney Run near Salisbury •...•.•.. 20 Gaging-station records ..•...... •...••• 11 at Ursina ...... 21 Kiskiminetas River basin: Green Lick Run at Green Lick Stony Creek at Ferndale, Pa .•...•...• 12 Reservoir...... 22 Conemaugh River at Seward ...•...... 12

ILLUSTRATIONS

Page Figure 1. Map showing location of gaging stations included in this report...... 2 2. Period of record of maximum annual peaks at gaging stations...... 4 3. Frequency of annual floods, all stations, period 1914-50 ••..• ·...•...... •...... 7 4. Frequency of annual floods, stations 4, 6, 9, 1q and 11, period 1914-50...... 8 5. Frequency of annual floods, stations 4, 6, 9, 1q and 11, period 1884-1950...... 8 6. Variation of mean annual flood with drainage area ...... •...... •...... 10

TABLES

Page Table 1. Ratios to mean annual floods, ba~e period 1914-50...... 5 2. Ratios to mean annual floods, base period 1884-1950...... 6 3. Computation of mean annual floods for period 1884-1950, Kiskiminetas and Youghiogheny River basins...... • . . • . . • • . . . . . • . . . • . . . • ...... • • . . • . . . . . • . . . • . . . . 9

iii

FLOODS· IN YOUGIDOGHENY AND KISKIMINETAS RIVER BASINS PENNSYLVANIA AND MARYLAND

FREQUENCY AND MAGNITUDE

INTRODUCTION by the suboffice, Max Noecker, engi­ neer-in-charge, in collaboration with engineers of the Water Resources Division, U. S. Geolog­ Engineers have long appreciated the fact ical Survey, Washington, D. C. that it is seldom economically sound to design hydraulic structures either for the maximum previous floods or for the computed maximum METHOD probable floods, unless failure of such struc­ tures involves loss of life or serious property With streamflow records available for gaging damage. Such floods may not occur more often, stations located on various sized watersheds on an average, than once in a hundred or pos­ in the area, the study resolved itself into sibly even several thousand years. In planning two parts: the determination of the flood­ sound design for structures, such as culverts frequency characteristics of the region ex­ or bridge·s, which may involve flood frequencies pressed as a curve in terms of the ratio of a of only 10 to 50 yr, the factors of economic~ given flood to the mean annual flood, and the and useful life of the structure should be con­ definition of a curve of mean annual flood ex­ sidered. pressed as a function of the drainage area. With these known factors, it is possible to In the past, records of streamflow have been compute the magnitude-frequency relation of so meager and of such short duration that litt~ floods at any location in the region. reliable information could be obtained on the magnitude and frequency of floods in any par­ ticular region. As a result it has been the RECORDS AVAILABLE tendency of engineers to overdesign, often causing needless expenditure. All gaging-station records of sufficient length in the two river basins in which the The accumulation of reliable streamflow rec­ peaks are not seriously affected by artificial ords over a relatively long period now permits regulation were used in this study. These satisfactory studies of flood probabilities in stations all located in Pennsylvania, are: many regions. 1. Stony Creek at Ferndale. This report presents a method, based on 2. Conemaugh River at Seward. actual flood data, for obtaining the magnitude 3. Conemaugh River at Tunnelton. and frequency of floods at any place in the 4. Kiskiminetas River at Avonmore. watersheds of the Youghiogheny and Kiskiminetas 5. Little Conemaugh River at East Conemaug~ River basins, an area comprising 3,651 sq mi 6. Blacklick Creek at Blacklick. in the upper Ohio River basin of western Penn­ 7. Loyalhanna Creek at Kingston. sylvania and Maryland. 8. Loyalhanna Creek at New Alexandria. 9. Youghiogheny River at Ohiopyle. The data contained in this report were com­ 10. Youghiogheny River at Connellsville. piled and prepared for publication under a 11. Youghiogheny River at Sutersville. cooperative agreement on water resources in­ 12. Casselman River at Markleton. vestigations between the Pennsylvania Depart­ 13. Big Piney Run near Salisbury. ment of Forests and Waters, and the Water Re­ 14. Laurel Hill Creek at Ursina. sources Division, U. S. Geological Survey. 15. Green Lick Run at Green Lick Reservoir. J. W. Mangan directs the surface-water inves­ tigations in Pennsylvania for the U. S. Geo­ The locations of these stations are shown logical Survey. The data presented in this on the map presented as figure 1. report were analyzed, and the text prepared, l 2 FLOODS IN PENNSYLVANIA AND MARYLAND

••

•I •

PENNSYLVANIA -wEST' ViRGINIA

( ...... ______\

I " j PENNSYLVANIA ( : ______./' 5 0 20 Miles

Figure 1.--Map showing location of gaging stations included in this report. FLOOD-FREQUENCY RELATIONSHIPS 3 Records for the following stations, operated Annual floods Partial-duration-series presently or in the past within this area, have not been used in this report: 1.16 0.5 1.58 1.0 Casselman River at Confluence, Pa., 2.00 1.45 Laurel Hill Creek at Confluence, Pa., 2.5::1: 2.0 Youghiogheny River at Youghiogheny River 5.52 5.0 Dam, Pa., 10.5 10 ~asselman River at Grantsville, Md., 20.5 20 Youghiogheny River at Oakland, Md., 50.5 50 Youghiogheny River at Friendsville, Md. 100.5 100 The first three stations listed were not used because they were affected by backwater Plotting positions for the greater part of the time. The records at the remaining stations were of too short In analyzing the re-lation between frequency duration to obtain satisfac~ory correlations and magnitude of floods, the discharges were with other stations necessary to extend them arranged by number in order of magnitude. to the length of the base period. (.See Ad­ Appropriate recurrence intervals were then justment to base periods.) assigned to each flood, depending upon the order number, the period of record, and any Whenever possible, gaging-station records additional historical information indicating were supplemented by historical flood data the frequency of recurrence. obtained prior to the systematic collection of stream-gaging records. Recurrence intervals were computed from the formula (li+l)/M, where~ equals number of years Tabulations of the momentary peak stages of record and M equals the order of relative and discharges at gaging stations during each magnitude of the event beginning with the high­ "water year" of record are presented in the est as one. In the case of a historical flood, last section of this report. The water year N is the number of years during which it is extends from October 1 to September 30. known that the flood was of the order assigned. This formula, adopted by the Geological Survey, is simple to compute, is applicable both to FLOOD-FREQUENCY RELATIONSHIPS annual-flood data and the partial-duration series, and gives results acceptably in con­ formance with some of the latest theories. Analysis of flood data Annual floods were plotted on a special In developing flood-frequency relationships form2 developed for analysis of flood frequen­ in this report, the annual-flood method was cies by the theory of extreme values.3 On the used. By this method each flood has been basis of this theory the discharge at a recur­ treated as an independent event, and ·only the rence interval of 2.33 yr is the same as the maximum momentary discharge occurring in each arithmetical mean of an infinitely long series water year of record was used. of annual floods and is known as the "mean annual flood." As generally is done with rel­ An objection often raised to the annual­ atively short series, such as are treated here, flood method is that it utilizes only one flood the value of the discharge at a recurrence in­ in each year and may discard one or more floods terval of 2.33 yr has been picked graphically that occurred during the year that may be hig~ from a flood-frequency curve and used as the than some of the annual floods in other years. mean annual flood. This objection is met by the partial-duration­ series method in which all floods are listed above a selected base irrespective of the num­ Adjustment to base periods ber of floods occurring in any time period. This method involves the difficult·y that flood Figure 2 shows graphically the length of peaks occurring close together may not be in­ usable records in the two basins. In order to dependent events, and some arbitrary criterion combine records, it is necessary for them to must be set up for separating such peaks. be on the same time basis. The longer the time basis, the more reliable is the resulting The methods used for analysis are statis­ frequency curve. The longest continuous rec­ tical, and a "complete" series such as the ord, Youghiogheny River at Ohiopyle (Confluence), annual-flood series can be treated by a rigid Pa., began in 1873; the next longest, Kiski­ statistical me~hod. minetas River at Avonmore, Pa., began in 1884. The objective of this study was to obtain a The partial-duration-series method tells composite frequency curve for the 67-yr period, how often, on the average, a given flood will ·1884-1950. The procedure adopted, using all occur; the annual-flood method tells how often, available data, was to compute the annual­ on the average, it will occur as an annual flood figures for years of missing record for peak. all stations. After computing them, they were not used directly as peak discharges for those The following table1 gives the comparative years but were used indirectly so as to obtain values of the recurrence intervals, in years, values for the mean annual flood based on a by the two methods. Both methods give essen­ tially the same results for recurrence inter­ vals greater than 10 yr. 2 Powell, R. W., A simple method of esti­ mating flood frequency, Civil Eng.,pp.l05-l06,. 1 Langbein, W. B., Annual floods and the Feb. 1943. partial-duration flood series, Amer. Geophys. 3 Gumbel, E. J., Floods estimated by the Union, Trans., vol. 30, p. 879, 1949. · probability methcd, Eng. News-Record, June 14, 1945. 4 FLOODS IN PENNSYLVANIA AND MARYLAND Reference no. 1880 1890 1900 1910 1920 1930 1940 1950

2 ------3 ,______------

4 5 f------r------6 ----r------r------1--- ___..._ ____-1------+------+-----i 7 1------r------1------r---

8 1-----1------r------t------1------~---

9 10 f------I-

I I r----1------1------+------+------+------+-----+-· 12 1-----1------1------

13 ----r------t------+-----~

14 f------

15 ,______------r------1------1------t------o~------+-----~

Figure 2.--Period of record of maximum annual peaks at gaging stations. uniform time period and the correct order num­ relationships, it was necessary to convert bers in the base period for the actual known them to a dimensionless basis. This was done peaks. by expressing each flood as a ratio to the mean annual flood for the particular station, In this report it did not appear feasible derived for a definite base period.· The mean to fill in or extend all records back to 1884. annual floods_for the base periods were deter­ Only five records, those for Avonmore, Black­ mined from the individual frequency graphs de­ lick, Ohiopyle, Connellsville, and Sutersville, scribed in the preceding section. were used for the period 1884-1950. All others were used for the period 1914-50. The initial Tables 1 and 2 list by order number and procedure was to work up composite frequency station the peak floods of only those years curves for all stations for the base period for which there is actual record, expressed as 1914-50, the five long-term stations for the a ratio to the mean annual flood. For the base period 1884-1950, a~d the five long-term period 1914-50, table 1 shows the medians for stations for the shorter period 1914-50. each order of flood computed for all stations and for the five stations with long-term rec­ ord. In table 2, medians were computed for Test for homogeneity each order of flood for the 67-yr stations. A test for homogeneity was applied to the individual station records in order to assure Composite flood-frequency graphs that all records represent part of a region having uniform frequency characteristics. In figures 3 to 5 the median ratios from This is a statistical test applied to the tables 1 and 2 were plotted against the recur­ slopes of the individual frequency graphs to rence intervals for the corresponding order determine whether deviations from an average numbers. Average frequency curves were drawn. slope are such as may be due to chance alone. It will be noted that the composite curve for The graphs were those for all stations for all stations, 1914-50 (fig. 3), is identical the 1914-50 period and the five long-term sta­ with that for the five index stations, 1914-50 tions for the 1884-1950 period. The graphs (fig. 4). For this reason the long-term com­ were drawn using only peaks of actual record, posite frequency curve (fig. 5), as defined with order numbers based on a complete listing by the five index stations, can be taken to as described in the prece.ding section. The represent the frequencies for the period 1884- test showed all records to be homogeneous for 1950 for all stations. If the curves of fig­ both base periods. ures 3 and 4 had not coincided, it would have beem necessary to compute a new curve from the curve of figure 5 by ratios representing Median flood-ratios the differences between the first two curves ~t specified recurrence intervals. In order to compare floods at different stations and combine them to define composite Table 1.-- Ratios to mean annual floods, base period 1914-50 Stations Recur- All Stations 4, 6. 9 10. 11 Order Station no. renee Number Median Number Median no. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 interva of itemf of items 1 5.36 4. 74 4.40 4.61 4. 5"0 3.50 4.19 3.12 2.94 2.62 3.20 4.06 2.12 5.00 38.0 14 4.12 5 3.12 2 2.30 1. 74 1. 74 1.89 1. 87 2.16 3.08 2.67 2.07 2.20 3.87 1.94 2.ll 19.0 13 2.11 5 2.07 3 2.17 1.84 1.64 1. 70 1.89 2.06 2.02 2.04 2.04 3.26 1. 67 1.95 12.7 12 1.98 4 2.03 4 2.05 1.59 1.56 1. 61 1.55 1.54 l. 75 1.54 1. 67 1.34 1.88 9.50 11 1.59 4 l. 58 5 1.93 1.50 1.50 1. 57 1.52 1.54 1.59 1.37 1.45 1. 79 1.24 1.86 7.60 12 1.53 5 1.54

6 1.91 1.48 1.35 1.50 1.45 1.40 1.54 1.45 1. 75 1.23 1.81 6.33 11 1.48 4 1.45 7 1.56 1.39 1.31 1.33 1.36 1.35 1.38 1.52 1.45 1.23 5.43 10 1.37 4 1.36 8 1.52 1.25 1.30 1.26 1.31 1.34 1.42 1.30 1.40 1.20 4.75 10 1.30 5 1.30 9 1.37 1.25 1.20 1.30 1.26 1.23 1.33 1.30 1.37 1.17 1.19 4.22 11 1.26 5 1.30 .10 1.32 1.24 1.18 1.30 1.17 1.27 1.28 1.18 1.42 1.16 3.80 10 1.26 5 1.27

11 1.24 1.16 1.20 . 1.16 1..24 1.14 1.21 1.16 1.17 1.16 3.45 10 1.16 5 1.16 12 1.15 1.15 1.19. t:22 1.12 1.12 1.22 1.16 3.17 8 1.16 3 1.15 13 1.13 1.19 1.24 1.11 1.17 1.10 1.12 1.19 1.06 1.06 2.92 10 1.12 4 1.14 14 1.10 1.06 1.06 1.11 1.04 1.10 1.12 1.11 1.03 1.01 2.71 10 1.08 3 1.06 ~ 15 1.00 t"i 1.11 1.06 1.05 1.06 1.09 1.06 .991 1.03 .993 2.53 10 1.06 3 1.06 0 16 .936 1.07 1.03 .946 1.02 .981 1.04 1.05 1.00 2.38 9 1.02 4 1.02 8 17 .927 1.01 .991 .919 .985 .981 1.03 1.04 1.00 2.24 9 .991 5 .991 ~ 18 .895 .988 1.00 .965 .905 .970 .965 .922 .964 2.11 9 .965 4 .968 ~ 19 .851 .958 .919 .995 .939 .878 .933 .955 .887 .913 .909 .950 2.00 12 .926 4 .936 g 20 .840 .910 .939 .913 .902 .948 .8'85 .857 .899 1.90 9 .902 5 .913 g{ 0 21 .818 .893 .928 .870 .817 .824 .897 .886 .885 .835 .826 .887 1.81 12 .878 5 .886 ....:: ::u 22 .755 .893 .846 .824 .897 .886 .812 .835 .880 .929 1. 73 10 .863 5 .886 t,tj 23 . 755 . 795 .803 .776 .. 894; .B23 .875 .810 .806 .835 .854 .914 1. 65 12 .816 5 .810 t"i ~ 24 .755 . 767 ':776 .793 .871 .806 .833 .751 829 1. 58 9 .793 4 .791 t-3 H 25 .741 • 752 .709 .793 .844 . 781 .810 .779 1.52 8 . 780 4 .766 0 ~ 26 . 709 .666 . 743 .814 . 781 . 738 .810 .755 1.46 8 . 749 4 . 760 ::X:: .666 H 27 .662 .695 . 726 . 728 .712 .814 . 738 .810 .738 1.41 10 .727 4 .732 1-cJ 28 .649 .695 .645 . 703 . 752 .785 .598 .687 .771 1.36 9 .695 2 .698 CIJ 29 .649 .671 .645 .662 .724 .785 .664 .682 1.31 8 .668 2 .684 30 .636 . 710 .625 .662 . 757 .602 . 780 .592 .641 .664 1.27 10 .652 4 .668

31 .624 .676 .625 .738 .683 .780 .641 .654 1.23 8 .665 4 .680 32 .624 .660 .605 .670 .594 . 736 . 639 .621 1.19 8 .632 4 .632 33' .611 .574 .643 ... 567 . 715 .579 .729 .598 .621 1.15 9 .611 4 .611 34 .525 . 5§_§_ .618 .549 .514 .688 .687 .466 .573 1.12 9 .573 3 .586 t--· -~ 35 .478 .512 - .459 .632 .563 .-680 .489 ~-~- ---, .!:>.L<::: ----s-~- r---_--;~ 36 .453 .526 .543 .495 .459 .606 .555 .594 ".445 .447 .546 1.06 11 .526 4 .549 37 .399 .455 .493 .472 .477 .419 .635 .530 .495 .571 .427 .450 1.03 12 .474 5 .495

\Jl 6 FLOODS IN PENNSYLVANIA AND MARYLAND

Table 2.--Ratios to mean annual floods, base period 1884-1950

Order Station no. Number Recurrence no. 4 6 9 10 11 of items Median interval 1 4.40 4.31 2.69 2.60 2.50 5 2.69 a78 2 2.35 3.78 2.66 2.36 2.50 5 2.50 b39 3 2.10 2.12 2.31 2.11 1.97 5 2.11 22.7 4 1. 98 2.26 1.97 3 1.98 17.0 5 1.93 1.93 1.85 1. 95 4 1.93 13.6 6 1.86 1. 78 2 1.82 11.3 7 . 1. 74 1. 79 1.63 1. 79 1. 73 5 1. 74 9. 71 8 1.65 1.62 1.63 1.72 1.62 5 1.63 8.50 9 1.54 1.55 1.52 3 1.54 7.56 10 1.54 1.44 1.53 1.48 4 1.50 6.80 11 1.51 1.38 1.30 3 1.38 6.18 12 1.50 1.33 1.40 1.30 4 1.36 5.67 13 1.48 1.44 1.32 1.37 4 1.40 5.23 14 1.35 1.44 1.31 1.37 1.28 5 1.35 4.86 15 1.31 1.41 1.30 1.35 4 1.33 4.53 16 1.26 1.34 1.28 1.31 4 L30 4.25 17 1.25 1. 27 1.21 1.25 1. 24 5 1.25 4.00 18 1.25 1.24 1.20 1.25 1.24 5 1.24 3. 78 19 1.22 1.24 1.19 1.18 1.22 5 1.22 3.58 20 1.18 1.24 1.18 1.20 4 1.19 3.40 21 1.16 1.18 1.12 1.10 4 1.14 3.24 22 1.15 1.19 1.15 1.12 1.10 5 1.15 3.09 23 1.19 1.11 1.09 1.06 4 1.10 2.96 24 1.08 1.17 1.10 1.07 1.06 5 1.08 2.83 25 1.14 1.07 2 1.10 2.72 26 1.06 1.12 1.06 1.05 4 1.06 2.62 27 1.02 1.02 1.04 1.05 4 1.03 2.52 28 1.04 1.02 1.01 1.02 1.04 5 1.02 2.43 29 .997 1.01 2 1.00 2.34 30 1.02 .992 .987 1.00 4 .996 2.27 31 1.01 1.01 .990 3 1.01 2.19 32 1.00 .950 .967 1.01 .982 5 .982 2.12 33 .926 .925 .967 .961 4 .944 2.06 34 .919 .900 .954 .948 4 .934 2.00 35 .910 .900 .898 .927 .940 5 .910 1.94 36 .871 .912 2 .892 1.89 37 .893 . 833 .875 .868 .905 5 .875 1.84 38 .893 .875 .868 .905 4 .884 1. 79 39 .876 .8ll .875 .854 .905 5 .875 1. 74 40 .852 .875 .854 .878 4 .864 1. 70 41 .819 .788 .849 3 .819 1.66 42 .819 .788 .836 .843 .845 5 .836 1.62 43 .776 .826 .828 3 .826 1.58 44 .767 .743 .787 .798 .820 5 .787 1.55 45 • 787 .820 2 .804 1.51 46 .752 .679 .774 . 787 4 .763 1.48 47 .774 .784 .775 3 .775 1.45 48 .726 .761 .784 .770 4 .766 1.42 49 .638 .754 .742 .770 4 .748 1.39 50 .638 .751 .717 3 .717 1.36 51 .710 .618 .728 . 705 4 .708 1.33 52 .710 .618 .725 .691 .705 5 • 705 1.31 53 ,.618 .725 .691 3 .691 1.28 54 .676 .599 . 702 .650 4 .663 1.26 55 .660 .599 . 702 .6~6 .650 5 .660 1.24 56 .660 .580 .641 3 .641 1.21 57 .643 .598 2 .620 1.19 58 .600 .652 .604 .575 4 .602 1.17 59 .600 .543 .636 .593 4 .596 1.15 60 .586 .526 .590 .568 4 .577 1.13 61 .491 .616 .552 3 .552 1.11 62 .543 .593 2 .568 1.10 63 .514 .474 .559 .538 4 .526 1.08 64 .507 .537 .530 3 .530 1.06 65 .493 .457 .548 .525 .492 5 .493 1.05 66 .538 .469 .472 3 .472 1.03 67 .419 .518 .469 .465 4 .467 1.01

a Highest since 1874. b Second highest since 1874. FLOOD-FREQUENCY RELATIONSHIPS 7

4.40 !

0

4.00 !

3.60 I

0 0 0 3.20 I ..J LL

..J ~ I :::l 2.80 z I z ' I v I ~ I z 2.40 v ~ I LLJ I ~ I v I 0 2.00 / t- l 0 I t- ! .... vv (U ~ 1.60 a:: I ~ I ~ I ~ I 9-~ 1.20 l.P-6" ~ .80 .-v/ ! ~ I ~ ~ I ~ i I .40 ~ 1.01 1.1 1.2 t.3 t.4L5 2 3 4 5 · 6 1 a 9 10 20 30 40 50 RECURRENCE INTERVAL, IN YEARS

Figure 3.--Frequency of annual floods, all stations, period 1914-50. 8 FLOODS IN PENNSYLVANIA AND MARYLAND

3.20 I 0 I I 0 0 2.80 ! 0 I ....J I v lL.. I ~ 2.40 I / :::::> I z I z I <( v ! 0 ~ ,z 2.00 <( I w I ~ I I ...... v / 0 1.60 0 ..... i _,R1 I ~ 0 ~ ..... I )Y6 <( I t .9- a::: 1.20 ..e15 ~ I .80 ~ ~ ~ ~ I ~ I ~ I ~ ~0 I LOI 1.1 1.2 1.3 14 1.5 2 3 4 5 6 7 8 9 10 20 30 40 50 RECURRENCE INTERVAL,IN YEARS

Figure 4.--Frequency of annual floods, stations 4, 6 1 9, 10, and 11, ~eriod 1914-50.

2.80 !

(/v 0 2.40 g0 / LL ...... / _J 2.00 <{ :;::) z z <( / i .RJ ~ 1.60 Vo z I ~ <( I p w I ~ I n/11 ::::E 1.2.0 ~ P6"" ....0 0 w ~ i €i .80 ~""' I a= rP" -sP I ~ I .40 ~~ I 1.01 1.1 1.2 l3 1.4 1.5 2 3 4 5 6 7 8 9 10 20 30 40 50 100 RECURRENCE INTERVAL, IN YEARS

Figure 5.--Frequency of annual floods, stations 4, 6, 9, 10, and 11, period 1884-1950. FLOODS IN. PENNSYLVANIA AND MARYLAND 9

MEAN ANNUAL·FLOOD Mean annual flood versus drainage area The adjusted values for mean annual floods Computation of comparable means were plotted against drainage areas in figure 6 and an average curve was obtained. The corre­ The value of the mean annual flood will vary lation of mean annual floods to drainage areas with the length of the record from which it is alone is remarkably consistent. derived and will be dissimilar for different periods of record even though the same number An attempt was made to investigate the re­ of ye~rs is being considered. In analyzing lation between mean annual floods and physical the relation between mean annual flood and characteristics, other than size of drainage drainage area, it is necessary to use values ·area, that might explain the spread of some for the mean annual flood that are based on points from the average curve. There was not the same time period. It is also desirable conclusive evidence to indicate that other to make this time period as long as possible. variables were sufficiently effective to in­ fluence the results of the present study. In this study the observed·mean annual floods, adjusted t·o the 67-yr period 1884-1950,. There are a few points that vary as much as were used in the development of the mean annual 15 to 20 percent from the average curve as flood-drainage area relation. The average ratio drawn, but these results are considered accept­ of the 67-yr to the 37-yr mean annual floods, able. OWing to the chance elements involved obtained from the five index stations (table 3~ and depending upon the length of record, there was 1.076. Values of the 37-yr mean annual is an expected variation in the mean annual floods for the other stations were adjusted flood that can be computed by statistical to the 67-yr values by applying the coefficient methods for any desired confidence interval. 1.076. A 95 percent confidence interval was used.

Table 3.--Computation of mean annual floods for period 1B84-1950 Kiskiminetas and Youghiogheny River basins (All gaging stations are located in Pennsylvania} I II Drain- Mean annual Mean annual Ratio No. Station age flood (cfs} flood (cfs} IIti area 1914-50 1884-1950 4 Kiskiminetas River at Avonmore------42,000 42,000 1.000 6 Blacklick Creek at Blacklick------11,500 12,000 1.043

9 Youghiogheny River at Ohiopy~e ------26,300 30,500 1.160 10 Youghiogheny River at Connellsville------31,500 35,600 1.130 11 Youghiogheny River at Sutersville------38,200 40,000 1.047 Avera~e------~ ------1.076 1 Stony Creek at Ferndale------451 11,000 11,800 2 Conemaugh River at Seward ------715 . 19,000 20,400 3 Conemaugh River at Tunnelton------1,358 34,000 36,600 4 Kiskiminetas River at Avonmore------1,723 42,000 42,000 5 Little Conemaugh River at East Conemaugh---- 183 6,250 6,120 6 Blacklick Creek at Blacklick------390 11,500 12,000 7 Loyalhanna Creek at Kingston------168 6,000 6,460 8 Loyalhanna· Creek at New Alexandria------265 7,400 7,960 9 Youghiogheny River at Ohiopyle------1,062 26,300 30,500 10 Youghiogheny River at Connellsville------1,326 31,500 35,600

11 Youghiogheny River at Sutersville~------1,715 38,200 40,000 12 Casselman River at Markleton------382 11,200 12,100 13 Big Piney Run near Salisbury------J---- 24.5 1,060 1,140 14 Laurel Hill Creek at Ursina------121 4,850 5,220 15 Green Lick Run at Green Lick Reservoir------3.07 280 301 10 FLOODS IN PENNSYLVANIA AND MARYLAND

100,000

g( v ~ ..... v 1- w v~ w 0 LL. 10,000 / (.) ~ iD ~ :::> (.) lY' ~ vv 0 0 / 0 ..J LL...... ,.. // a:: 1000 >- 800 / !'(') 600 /v !'(') ~ /v _J 400 <( v z:::> z / <( 200 z <( w ~ 2 4 6 8 10 100 1000 10,000 DRAINAGE AREA, IN SQUARE MILES

Figure 6.--Variation of mean annual flood with drainage area. The significance of this is that 95 percent of would be desirable in the definition of mean the time the mean annual flood, on the basis annual floods. However, the consistency of of chance alone, can be expected to fall with­ the plotting of points on figure 6 gives some in the computed limits. The deviations from confidence in the lower part of the curve. the average curve are within these limits and • are therefore considered satisfactory. The results are applicable to unregulated conditions only. Some of the stations used are slightly affected by regulation. However, APPLICATION OF FLOOD DATA it is likely that the annual peak discharges for these stations have not been materially Two basic curves have been developed from affected. Other stations have been materially the available data that can be used to deter­ affected in recent years, but the peak dis­ mine the frequency relationship of any area, charges for these years were not used. gaged or ungage~ in the Youghiogheny and Kiskiminetas River basins. To determine the frequency curve at a de­ sired site, enter the ~urve of figure 6 with Figure 5 represents the general frequency the known drainage area and obtain the value relation, expressed as a ratio to the mean of the mean annual flood. Then from the curve annual flood, at any point within the two of figure 3, select values at several recur­ basins. rence intervals of the ratio to mean annual flood. These ratios when multiplied by the Figure 6 represents a satisfactory relation mean annual flood will give the values of peak between drainage area and mean annual flood discharge that can be plotted against the cor­ for any point within the two basins with a responding recurrence intervals to define the drainage area greater than 3 sq mi. desired frequency curve. These curves should not be extrapolated To illustrate the use of the data, let us beyond the limits of the available data be­ suppose that it is desired to determine the cause this procedure could lead to serious flood frequency curve for an ungaged site, error. within this area, that has a drainage area of 100 sq mi. Only two station records were available on drainage areas less than 100 sq mi. The size From figure 6, it is found that the mean of drainage area generally has not been found annual flood on a watershed of 100 sq mi is to have any effect on the characteristics of 4,200 cfs. the frequency curve. More small-area records GAGING-STATION RECORDS 11 From figure 5, the values of ratio to mean GAGING-STATION RECORDS annual flood have been selected arbitrarily at recurrence intervals of: Annual-peak gage heights and discharges at gaging stations used in this report have been 1.1, 1.5, 2.33, 5, 10, 25, and 50 yr. tabulated in this section. These ratios were found to be: The annual peaks listed were the highest momentary peaks in each water year, which in­ 0,55, 0.77, 1.00, 1.38, 1.71, 2.16, and cludes the period October 1 to September 30. 2.50, respectively. The water year was used rather than the cal­ endar year because September and October are These values when multiplied by the mean usually months of low flow; hence the use of annual flood, 4,200 cfs, give discharges of: the water year tends to eliminate any influ­ ence tbat one annual flood might have upon 2,310, 3,230, 4,200, 5,800, 7,180, 9,Q70, another. Although the maximum flood in each and 10,500 cfs, respectively. water year is listed,· the date shown is for the calendar year in which the event occurred. The frequency curve for the site may be obtained by plotting these discharges against Gage heights represent the water level in the corresponding recurrence intervals. feet above an arbitrary datum that is refer­ enced to local benchmarks at the gage. At If it is desired to determine only the dis­ most stations the gage datum has been tied in­ charge for a specific recurrence interval for to the level net of the Coast and Geodetic the site, the frequency curve need not be Survey, and for these stations the mean-sea­ plotted. For example, if the discharge for a level elevation of the datum of gage is given 25-yr flood is required, it is necessary only under "Gage" in descriptive material. The to determine the mean annual flood (4,200 cfs) gage heights were generally obtained from and the ratio for the 25-yr recurrence interval water-stage recorder charts, recorded flood ~.16). By multiplying these two factors, the marks, or graphs based on gage readings by an 25-yr flood is found to be 9,070 cfs. observer. Peak discharges are listed in cubic feet STAGE FREQUENCIES per second. This term in abbreviated form is designated in the tables and station records Information on stage frequency rather than as "cfs." Peak discharges are computed di­ discharge may sometimes be desired. Where the rectly from the peak gage heights by means of relation between stage and discharge is known, the stage-discharge relation. it is possible to convert from a discharge­ frequency curve to a stage-frequency curve. Before data from these stations were used, This relation is usually known only at gaging­ the stage-discharge relation during the period station sites, and no general stage-frequency of record at each gaging station was reviewed relationships can be formulated for a region. and records were revised where necessary .. Most of the.se revisions were based on data Although for Pennsylvania streams the re­ obtained after the discharges were already lation at high stages between stage and.dis­ published. For the most part, the changes charge at any particular site is fairly stable, were made in the interests of consistency in there is enough change so that current infor­ this report. Some records involve significant mation should always be utilized. For this differences with already published figures. reason no attempt has been made to furnish These major revisions are being published in information on stage frequencies in this re­ the water-supply papers and will supersede port, except that gage heights are shown for earlier figures. Where no such revisions are annual floods at the individual gaging sta­ made, it can be assumed that figures originally tions. The necessary data, whereby stage published can be used without loss of accuracy. frequencies may be determined at any gaging­ station site in these basins, is on file at Source of the data is indicated under the offices of the U. S. Geological Survey in "Remarks" for records other than those collected Harrisburg and Pittsburgh, Pa. by the U. S. Geological Survey. 12 FLOODS IN PENNSYLVANIA AND MARYLAND

Kiskiminetas River basin 1 (1) Stony Creek at Ferndale, Pa.

1 11 Location.--Lat 40°17 10 , long. 78°55 1 10", at highway bridge at Ferndale, Cambria County, 0.4 mile downstream from Bens Creek, 1.2 miles upstream from Johnstown city limit, and 5.2 m:+les upstream from confluence with Little Conemaugh River. Drainage area.--451 sq mi; 467 sq mi at site in Johnstown prior to 1939. Gage.--Nonrecording gage at Johnstown, July 1913 to March 1936; datum of gage 1,154.0 ft above mean sea level. Nonrecording gage at Ferndale, December 1938 to May 1940 and recording gage thereafter; datum of gage 1,183.84 ft above mean sea level. Stage-discharge relation.--Defined by current-meter measurements below 12,000 cfs and extended to 59,000 cfs on basis of slope-area and contracted-opening measurements. Remarks.--Regulation by mine pumpage and by reservoirs above station, the five largest of which have a combined capacity of 1,788,000,000 cu ft. Some diversion from Quemahaning Reservoir to Cambria plarit of Bethlehem Steel Co., and from Mill Creek, Dalton Run, and North Fork Bens Creek Reservoirs for water supply of city of Johnstown. Annual peak discharges not materially affected by regulation or diversion. Records from July 1913 to March 1936, and December 1938 to September 1941 in reports of Pennsylvania Department of Forests and Waters. Annual flood of 1937 from crest elevation furnished.by city engineer of Johnstown. Annual flood for 1938 computed from U. S. Weather Bureau gage records.

Annual flood stages and discharges Gage Discharge Gage Discharge Date ~eight (cfs) Date height (cfs) \feet) (feet) 1914, Mar. 30------7.85 ------5,260 1933, Mar. 15------11.72 ------11,000 1915, Jan. 7------10.70 ------9,360 1934, Jan. 7------8.9 ------6,720 1916, Mar. 28------11.30 ------10,300 1935, Aug. 2------9.26 ------7,280 1917, Mar. 12------14.00 ------15,100 1936, Mar. 18------30.26 ------59,000 1918, Feb. 26------12.7 ------12,700 1937, Apr. 26------18.8 ------25,300 1919, May 10------8.15 ------5,780 1937, Oct. 28------10.0 ------8,300 1920, Mar. 12------11.2 ------10,200 Change in site and datum 1921, Mar. 3------8.98 ------6,860 1939, Feb. 3------8 8 ------9,240 1921, Nov. 28------13.7 ------14,500 1940, Mar. 31----;...- 13.3 ------23,900 1923, Feb. 2------7.1 ------4,390 1941, June 5------12.27 ------22,600 1924, Mar. 29------16.9 ------21,000 1942, Apr. 9------8.72 ------9,000. 1925, Feb. 11------10.0 ------8;300 1942, Dec. 30------11.07 ------17,200 1926, Feb. 23------10.0 ------8,300 1944, Mar. 17------7.90 ------7,140 1927, Jan. 22------10.96 ------9,840 1945, Mar. 6------11.97 ------21,200 1928, May 1------13.23 ------13,600 1946, June 2------10.95 ------16,700 1929, Feb. 26------9.15 ------7,140 1947, June 8------6.85 ------4,980 1930, Feb. 25------9.90 ------8,150 1948, Apr. 14------9.78 ------12,100 1931, Apr. 4--'----- 9.02 ------6,860 1949, Jan. 26------8.15 ------7,800 1932, Apr. 1------9.1 ------7,000 1950, Mar. 28------9_.90 ------12,400

(2) Conemaugh River at Seward, Pa.

11 Location.--Lat 40°25'10 , long. 79°01'40", at highway bridge at Seward, Westmoreland County, 2 miles downstream from Findley Run, and 9 miles northwest of Johnstown. Drainage area.--715 sq mi.

Gage.--Reco~ding gage. Datum of gage is 1,075.64 ft above mean sea level, unadjusted. Stage-discharge relation.--Defined by current-meter measurements below 21,000 cfs and extended to 90,000 cfs on basis of contracted-opening measurement. Historical data.--Flood of March 18, 1936; 90,000 cfs (gage height, 26.4 ft) from floodmarks. Remarks.--Regulation by steel mills and by several reservoirs above station, the eight largest of which have a combined capacity of 2,060,170,000 cu ft. Annual peak discharges not materially affected by regulation. KISKIMINETAS RIVER BASIN 13

(2) Conemaugh River at Seward, Pa.--continued

Annual flood stages and discharges Discharge Discharge Date {cfs) Date (cfs)

1936, Mar. 18------26.4 ------90,000 1944, Mar. 17------8.39 ------13,200 1945, Mar. 6------13.76 ------30,200 1939, Feb. 3------9.00 ------15,100 1946, June 2------11.27 ------22,000 1940, Mar. 31------15.22 ------35,000 1947, June 8 ------6.75 ------8,650 1941, June 5------13.15 ------28,200 1948, Apr. 14------11.04 ------21,000 1942, Apr. 9------10.07 18,200 1949, Jan. 26------8.37 ------13,200 1942 Dec. ------10.80 20 400 30------12.70 --:-----~---- 26 500 1950 Mar. 28------

(3} Conemaugh River at Tunnelton, Pa.

11 11 Location.--Lat 40°27 1 15 , long. 79°23 130 , at highway bridge at Tunnelton, Indiana County, 0.9 mile downstream from Boatyard RUn, 3t miles southeast of Saltsburg, and 5.5 miles upstream from con­ fluence with Loyalhanna. Creek •. Drainage area. --1 ,3_58 sq mi. Gage.--Nonrecording gage. Datum of gage is 844.64 ft above mean sea level, datum of 1929.

~tage-discharge relation.--Defined by current-meter measurements throughout. Remarks.--Regu1ation by steel mills and by several reservoirs above station, the eight largest of which have a combined capacity of 2,060,170,000 cu ft. Annual peak discharges not materially affected by regulation.

Annual flood stages and discharges Discharge Discharge Date (cfs) Date (cfs)

1940, Mar. 31------20.18 ------55,600 1946, Jure 13------14.6 ------33,600 1941, June 5------16.9 ------42,300 1947, June 8------10 .• 1 ------17,900 1942, Apr. 10-'----- 15.3· ------36;200 1948, Apr. 14------16.5 ------40,800 1942, Dec. 30------19.6 ------53,10el 1949, Jan. 27------10.6 ------19,500 1944, Mar. 17------11.6 ------22,800 1950, Mar. 28------12.9 ------27,300 1945 Mar. 7------21.0 ------59 200 14 FLOODS IN PENNSYLVANIA AND MARYLAND

(4) Kiskiminetas River at Avonmore, Pa.

11 11 Location.--Lat 40°32 105 , long. 79°27 1 55 , at highway bridge at Avonmore, Westmoreland County, 1 mile above mouth of Long Run. Drainage area.--1,723 sq mi. Gage.--Nonrecording gage May 1907 to July 1937. Datum of gage is 805.64 ft above mean sea level. Stage-discharge relation.--Defined by current-meter measurements below 30,000 cfs and extended to 185,000 cfs on basis of slope-area measurement. Remarks.--Regulation by steel mills, since 1942 by Loyalhanna Creek Reservoir and other reservoirs above station, the nine largest of which have a combined capacity of 2,108,300,000 cu ft. Annual peak discharges not materially affected by regulation. Records from May 1907 to September 1941 in reports of Pennsyl,vania Department of Forests and Waters. Records prior to May 1907 from Water Supply Commission of Pennsylvania, Water Resources Inventory Report, Part 8, Floods (computed from Signal Service and Weather Bureau gage readings at Saltsburg). Records after July 1937 computed on basis of record of recording gage at Vandergrift, drainage area 1,825 sq mi.

Annual flood stages and discharges Discharge Discharge Date ( cfs) Date (cfs)

1884, Feb. 6------24.1 ------52,900 1916, Mar. 22------20.0 ------37,500 1885, Jan. 17------16.4 ·------25,200 1917, Jan. 22------24.0 ------52,500 1886, Jan. 5------19.1 ------34,400 1918, Feb. 20------22.0 ------44,500 1886, Dec. 14------13.8 ------17,600 1919, Jan. 2------16.2 ------24,600 1888, Aug. 21------31.8 ------88,000 1919, Nov. 27------20.3 ------·-- 38,600 1889, .June 1------29.8 ------78,000 1921, Jan. 23------15.6 ------22,800 1890, Mar. 23------17.8 ------29,800 1921, Nov. 29------24.65 ------·54,900 1891, Feb. 17------30.4 ------81,000 1923, May 13------18.0 ------30,500 1892, .Jan. 14------15.1 ------21,300 1924, Mar. 30------24.0 ------52,500 1893, Feb. 11------15.2 ------21,600 1925, Feb. 12------17.8 ------29,800 1894, May 20------19.5 ------35,800 1926, Sept. -6------18.5 ------32,200 1895, Jan. 8------19.8 ------36,800 1927, Jan. 22------21.3 ------42,000 1927, Oct. 20------25.1 ------56,900 1902, Mar. 1------26.4 ------62,300 1929, Feb. 26------16.96 ------27,000 1903, Mar. 1------16.4 ------25,200 1930, Feb. 25------23.3 ------49,700 1904, Jan. 23------21.8 ------43,800 1931, Apr. 4------20.2 ------38,200 1905, Mar. 8------20.4 ------38,900 1932, Apr. 1------18.3 ------31,600 1906, June 7------19.1 ------34,400 1933, Mar. 15------23.0 ------48,500 1907, Mar. 14------33.8 ------98,900 1934, Sept. 30------14.90 ------20,700 1908, Mar. 19------30.8 ------83,000 1935, Aug. 4------18.6 ------4-- .32,600 1909, Feb. 24------17.2 ------27,700 1936, Mar. 18------47.2 ------185,000 1910, Feb. 17------23.7 ------51,300 1937, Apr. 26------28.8 ------73,100 1911, Sept. 15------21.5 ------42,800 1937, Dec. 18------37,500 1912, Mar. 21------28.0 ------69,500 1939, Feb. 4------28,400 1913, Jan. 8------22.2 ------45,300 1940, Mar. 31------62,800 1914, Mar. 17------17.2 ------27,700 1941, June 5----7------48,900 1915 Feb. 2------21.40 ------42 400 KISKIMINETAS RIVER BASIN 15

(5) Little Conemaugh River at East Conemaugh, Pa.

Location.--Lat 40°20 1 35", long. 78°53'05", at highway bridge at East Conemaugh, Cambria County, 0.3 mile downstream from Clapboard Run and 2.5 miles upstream from confluence with Stony Creek.

Drainage area.--183 sq mi.

Gage.--Recording gage. Datum of gage is 1,207.92 ft above mean sea level (Corps of Engineers ----oenchmark) •

Stage-discharge relation.--Defined by current-meter measurements below 5,200 cfs and extended to 29,000 cfs on basis of slope-area measurement.

Historical data.--Flood of March 17, 18, 1936, 28,800 cfs by slope-area determination.

Remarks.--Regulation by small reservoirs and diversion works above station. Annual peak discharges not materially affected by regulation.

Annual flood stages and discharges

Gage Discharge Gage Discharge Date height (cfs) Date height (cfs) (feet) (feet) 1936, Mar. 17, 18------28,800 1945, Mar. 6<------8.03 ------9,350 1946, June 2------6.29 ------5,800 1940, Mar. 30------8.80 ------11,800 1947, June 8------4.83 ------2,950 1941, June 5------7.19 ------7,530 1948, Apr. 14------6.47 ------6,220 1942, Apr. 9------·-·- 6. 77 ------6,590 1949, July 12------5.36 ------3,860 1942, Dec. 30------· 7.29 ------7,410 1950, Mar. 28---,--- 6.22 ------5,590 1944, Mar. 17------6.06 ------4,550

(6) Blacklick Creek at Blacklick, Pa.

Location.--Lat 40°28'25", long. 79°12'15", at highway bridge at Gratton, a quarter of a mile north­ west of Blacklick, Indiana County, and three-quarters of a mile downstream from Two Lick Creek.

Drainage area.--390 sq mi.

Gage.--Nonrecording gage. Datum of gage is 945.94 i't above mean sea level (Pennsylvania State ~ghway benchmark).

Stage-discharge relation.--Defined by current-meter measurements below 18,000 cfs and extended to 52,000 cfs on basis of slope-area determination.

Remarks.--Records August 1904 to December 1905 and January 1907 to September 1941 in reports of Pennsylvania Department of Forests and Waters.

Annual flood stages and discharges

Gage Discharge Gage Discharge Date height (cfs) Date height (cfs) (feet) (feet)

1905, Mar. 21-----­ 8.6 8,920 1927, Oct. 20-----­ 9.80 12,200 1905, Dec. 3------­ 11.2 16,900 1929, Feb. 26-----­ 8.10 7,660 1907, Mar. 14-----­ 15.4 45,400 1930, Feb. 25-----­ 9.70 11,900 1908, Mar. 19-----­ 11.3 17,300 1931, Apr. 4------­ 9.30 10,800 1909, Feb. 24-----­ 8.8 9,460 1932' Apr. 1------­ 7.5 6,310 1910, Jan. 18-----­ 10.97 16,100 1933, Mar. 15------9.28 10,800 1911, Jan. 14-----­ 10.2 13,400 1912, Sept. 3-----­ 12.9 25,500 1935, May 10------­ 8.30 8,150 1913, Jan. 8------­ 10.5 14,300 1936, Mar. 18-----­ 15.88 51,700 1914, May 6------­ 8.0 7,420 1937, Jan. 25-----­ 8.8 9,460 1915, Jan. 7------10.72 14,900 1937' Dec. 18-----­ 10.3 13,700 1915, 0ct. 19-----­ 10.7 14,900 1939, Jan. 31-----­ 7.8 .6, 960 1917, Jan. 22-----­ 11.3 17,300 1940, Mar. 31-----­ 11.5 18,100 1918, Feb. 20------10.8 15,300 1941, June 5------­ 8.0 7,420 1918, 0ct. 31-----­ 7.9 7,190 1942, Apr. 9------­ 9.01 10,000 1920, June 17-----­ 10.5 14,300 1942, Dec. 30-----­ 11.76 19,500 1921, May 5------­ 7.3 5,890 1944, Mar. 17-----­ 8.1 7,660 1921, Nov. 29-----­ 9.85 12;200 1945, Mar. 6------­ 10.4 :).4,000 1923, May 13------­ 9.5 11,400 1946, June 13----.-­ 11.65 18,500 1924, June 29-----­ 12.2 21,500 1947, June 8------­ 7.10 5,490 1925, Feb. 11-----­ 7.2 5,690 1948, Apr. 12-----­ 10.7 14,900 1926, Sept. 5-----­ 8.9 9,730 1949, Jan. 24-----­ 7.65 6,520 1927, Jan. 22------9.40 11,100 1950, Ju1y 5------7.90 7,190 16 FLOODS IN PENNSLYVANIA AND MARYLAND

(7) Loyalhanna Creek at Kingston, Pa.

Location.--Lat 40°17'35", long. 79°20 1 25", at Kingston, Westmoreland County, 60ft downstream from highway bridge, 150 ft upstream from Millers Run, 1.9 miles upstream from Ninemile Run, and 3 miles southeast of Latrobe. Drainage area.--168 sq mi.

~--Recording gage. DatUm of gage is 1,014.16 ft above mean sea level, datum of 1929 (Corps ---oY Engineers benchmark). Stage-discharge relation.--Defined by current-meter measurements below 8,200 cfs and extended to 21,000 cfs by logarithmic plotting.

Historical data.--Flood of March 17 or 18, 1936, reached stage of 14.5 ft; discharge 21,000 cfs. Remarks.--Regulation by Trout Run Reservoir (capacity, 48,130,000 cu ft) and diversion work at Kingston. Annual peak discharges not materially affected by regulation or diversion.

Annual flood stages and discharges Gage Discharge Gage Discharge Date height (cfs) Date height (cfs) (feet) (feet) 1936, Mar. 17 or 18- 14.5 ------21,000 1945, Mar. 6··------10.00 ------9,100 1946, June 2------9.46 ------8,140 1940, Mar. 30------9.83 ------8,710 1947, June 8------7.57 ------4,760 1941, June 5------10.06 ------9,300 1948, Apr. 14------9.22 ------7,570 1942, Apr. 9------8.72 ------6,640 1949, Jan. 26------7.74 ·------4,900 1942, Dec. 30------9.17 ------7,570 1950, Jan. 7------7.32 ------4,270 1944 Ma 7------7.61 ------4,760

(8) Loyalhanna Creek at New Alexandria, Pa.

Location.--Lat 40°23 1 40", long. 79°25'53", at highway bridge at New Alexandria, Westmoreland County, lt miles downstream from Crabtree Creek. Drainage area.--265 sq mi; 270 sq mi at site in use prior to August 1913.

~--Nonrecording gage October 1910 to August 1918, August 1919 to July 1923, and November 1925 ~September 1940. Datum at New Alexandria site 917.26 ft above mean sea level (general adjust- ment of 1912). Stage-discharge relation.--Defined by current-meter measurements below 3,300 cfs and extended to 31,000 cfs on basis of discharge measurements up to 14,000 cfs at Loyalhanna Creek Dam site and on basis of slope-area and contracted-opening measurements. Remarks.--Regulation by Trout Run Reservoir (capacity, 48,130,000 cu ft). Annual peak discharges not materially affected by regulation. Records August 1919 to July 1923, anQ November 1925 to September 1940 in reports of Pennsyl­ vania Department of Forests and Waters. Records July 1910 to August 1913 in reports of Penn­ sylvania Department of Forests and Waters are incomplete. Unpublished records August 1913 to August 1918 considered unreliable.

Annual flood stages and discharges Gage Discharge Gage Discharge Date height (cfs) Date height (cfs) (feet) (feet) 1918, Feb. 9------10.4 6,800 1930, June 10------10.1------6,500 ------1931, Apr. 4------10.3------6,700 1920, June 17------8. 70 ------4,900 1932, Jan. 30------7.2------3,400 1921, Jan. 8------7.2 ------3,400 1933, Mar. 15------12.3------9,200 1921, Nov. 28------·- 10.60 ------7,000 1934, Aug. 16------6.78------3,100 1923, May 13------7.6 3,800 1935, Aug. 3------16.0------16,000 ------1936, Mar. 18------20.96------31,000 1926, Sept. 6------9.8 ------6,100 1937' Apr. 26------15.09------14,000 1927, Jan. 21------8.95 ------5,200 1937, Oct. 28------9.8------6,100 1927, Oct. 20------12.65 ------9,700 1939, Feb. 3------8.7------4,900 1929, Feb. 26------9.3 ------5,500 1940, Mar. 31------12.9------10,000 FLOODS IN PENNSYLVANIA AND MARYLAND 17 Youghiogheny River Basin

(9) Youghiogheny River at Ohiopyle, Pa.

11 Location.--Lat 39°47 1 17", long. 79°29 1 44 , at highway bridge in Ohiopyle, Fayette County, half a mile upstream f om Meadow Run.

Draina~e area.--1, 62 sq mi; 1,029 sq mi at site of Weather Bureau gage at Confluence used prior to. 927. Gagp --Prior to. De ember 1927, Weather Bureau nonrecording gages at Confluence; thereafter, West nn Power Co. ecording gage at Ohiopyle. Datum of recording gage 1,198.91 ft above mean sea level. Stage-discharge re ation.--Defined by current-meter measurements below 16,000 cfs and extended to 83,000 crs on b< sis of area-velocity studies. Historical data.-- lood of March 18, 1936, known to be highest and flood of March 29, 1924, second highest since 1 73. Remarks.--Regulatipn since July 1943 by Youghiogheny River Reservoir and since 1925 by Deep Creek Reservoir (comb ned capacity, 352,770 acre-ft). Annual peak discharges not materially affected by regulation. Records 1924 and 1928 to 1942 furnished by West Penn Power Co.; gage-height records 1873 to 1923, and 19 5-27 from graphs based on nonrecording gage record at Confluence as published in reports of t e U. s. Weather Bureau. Ohiopyle record extended back to 1884 by this metbod.

Annual flood stages and discharges Gage Discharge Gage Discharge Date height (cfs) Date height (cfs) (feet) (feet) 1874, Jan. 7------10.9 ------26,300 £909, Feb. 24------8.7 ------16,400 1875, Aug. 2------16.1 ------49,700 910, June 19------13.1 ------33,400 187:6, Sept. 18---- - 14.0 ------39,500 1911, Jan. 30------13.2 ------33,800 1877, Jan. 16------12.6 ------·33, 900 1912, Mar. 21------18.1 ------~-----59,000 1877, Nov. 24------13.7 ------38,000 1913, Jan. 8------11.5 ·------26,700 1879, Jan. 28------12.1 ------·31, 200 1913, Nov. 16------10.7 ------23,600 1880, Feb. 13------13.0 ------34,700 1915, Jan. 7------11.2 ------25,500 1881, Feb. 12-----r-- 14.5 ------42,000 1916, Mar. 22------13.5 ------35,200 1882, Feb. 21-----r-- 12.3 ------31,600 1917, Jan. 22------14.6 ------40,500 1883, Feb. 7------~- 16.1 49,700 1918, Feb. 20------12.'5 30,800 ------25,900 1884, Feb. 5---·---~- 15.5 ------47,000 1919, Jan. 1------11.3 ------1885, Jan. 17-----r-- 13.3 36,100 1920, June 17------12.1 ------·29,100 ------10.1 21,400 1886, Jan. 5------~- 11.0 ------26,700 1921, Mar. 3------1887, Feb. 4------~- 11.7 29,500 1921, Nov. 28------11.5 26,700 1888, Aug. ------68,800 1923, Feb. 10.1 ------21,400 21----- ~-· 19.5 ------~-- 13------1889, May 31------~- 16.1 49,700 1924, Mar. 29------a13.0· 81,000 ------18,800 1890, Mar. 22----- ~- 14.0 ------39,500 1925, Feb. 12------9.4 ------1891, Feb. 17------14.9 ------··· 44,000 1926, Feb. 22------9.7 ------19,900 1892, Jan. 14------11.8 ------29,500 1927, Jan. 21------10.7 ------23,600 1893, Feb. 10------12.0 ------30,400 Change in site and datum 1894, Feb. 10------10.1 ------23,200 1928, May 1------9.23 ------32,300 1895, Jan. 8------13.4 ------36,600 1929, Feb. 27------6.2£ ------18,100 1896, July 25·------14.5 ------42,000 1929, Oct. 3------7.33 ------24,000 1897, Feb. 22------16.0 ------49,700 1931, Apr. 4------6.27 ------16,700 1898, Mar. 25------9.8 ------22,100 1932, Apr. 1------7.11 ------22,200 1899, May 18------12.5 ------·32, 500 1933, Mar. 14------8.94 ------36,800 1900, Feb. 8------8.0 ------15,800 1901, Apr. 1------·12.1 ------31,200 1935, Jan. 22------· 7.18 ------22,900 1902, Feb. 28------13.3 ------36,100 1936, Mar. 18------13.3C ------82,100 1903, Feb. 4------·11. 0 ------26,700 1937, Apr. 26------10.74 ------54,200 1904, Jan. 22------·14 .3 ------39,000 1937, Oct. 28------8.86 ------36,300 1905, Mar. 21------10.3 ------22,100 1939, Feb. 3------8.15 ------30,100 1906, Jan. 23------10.8 ------24,000 1940, Mar. 31------7.79 ------27,400 1907, Mar. 14------20.1 ------70,600 1941, June 5------9.34 ------40,400 1908, Feb. 15------14.5 ------40,000 1942_, Apr. 10---.--- 6.69 ------19,400 a Ohiopyle site and datum. 18 FLOODS IN PENNSYLVANIA AND MARYLAND

(10) Youghiogheny River at Connellsville, Pa.

Location.--Lat 40°01'05", long. 79°35 1 40", at Crawford Avenue Bridge in Connellsville, Fayette County, three-quarters of a mile upstream from Mounts Creek. Drainage area.--1,326 sq mi.

~--Nonrecording gage prior to August 1928 and recording gage thereafter. Datum of gage is -~0.13 ft above mean sea level ( & Ohio Railroad benchmark). Stage-discharge relation.--Defined by current-meter measurements below 55,000 cfs and extended to 93,000 cfs. Historical data. --Flood of April 12•, 1860, reached stage of 16.5 ft ·(prior to destruction of slackwater dams). Remarks.--Regulation since July 1943 by Youghiogheny River Reservoir and since 1925 by Deep Creek Reservoir (combined capacity, 352,770 acre-ft). Annual peak discharges not materially affected by regulation. Records from July 1908 to September 1941 in reports of Pennsylvania Department of Forests and Waters. Annual floods prior to 1909 from Water Supply Commission of Pennsylvania Report, Part 8, Floods. (Record for 1891 computed from Weather Bureau gage readings at West Newton. Records for 1896-1908 computed from Trotter Water Co., gage readings}.

Annual flood stages and discharges Discharge Discharge Date (cfs) Date (cfs)

1888) Aug. 21-22---- 17.8 ------70,000 19~8, Feb. 20------14.0 ------·42,000 1919, Jan. 1------11.51 ------27,900 1891, Feb. 17------14.7 ------46,600 1920, Mar. 13------12.13 ------30,900 1921, Mar. 3------10.10 ------21,500 1896, July 25------15.0 ------48,600 1921, Dec. 24-'------11.60 ------28,400 1~97, Feb. 23------16.7 61,200 1923, Feb. 2------8.9 ------16,700 1898, Aug. ------11------11.2 ------____ ....; _____ 26,400 1924, Mar. 29------19.4 ------84,000 1899, May 18------13.0 35,800 1925, May 10------9. 70 ·------19,900 1900,----(less than) 8.9 ------16,700 1926, Feb. 23------10.4 ------22,800 1927, Jan.'22------11.8 ------29,400 1902, Feb. 28------15.8 ------54,400 1928, May 1------13.7 ------40,000 1903, Feb. 28------12.7 ------34,200 1929, Feb. 27------9.48 ------19,100 1904, Mar. 1------13.7 ------4Q,OOO 1929., Oct. 3------12.00 ------30,400 1905, Mar. 21------12.0 ------30,400 1931, Apr. 4------9.95 ------21,100 1932, Apr. 1------11.00 ------25,500 1907, Mar. 14------18.4" ------75,200 1933, Mar. 14------14.9 ------48,000 1908, Feb. 15------14.4 ------44,600 1934, .Mar.4------10.77 ------24,600 1909, Feb. 24---·---- 9.36 ------·18, 700 1935, Jan. 22------10.83 ------24,600 1910, June 19------13.09 ------36,400 1936, Mar. 18------20.28 ------92,500 1911, Jan. 30------12.98 ------35,800 1937, .Apr. 26------15.87 ------55,100 1912, Mar. 21------17.28 ------66,000 1937, Oct. 28------14.35 ------44,600 1913, Jan. 8------13.50 ------38,800 1939, Feb. 3------13.37 ------38,200 1913, Nov. 16------11.50 ------27,900 1940, Mar. 31------'-- 13.16 ------37,000 1915, J:an. 7------12.13 ------30,900 1941, June 5------17.02 ------63,600 1916, Mar. 22------15.00 ------48,600 1942, Mar. 9------10.62 ------23,700 1917 Jan. 22------· 15.20 ------50,000 YOUGHIOGHENY RIVER BASIN 19

(11) Youghiogheny River at Sutersville, Pa.

11 Location.--Lat 40°14 1 25", long. 79"48 1 25 , at Sutersville, Westmoreland County, 500ft upstream from highway bridge and 2.1 miles downstream from Sewickley Creek. Drainage area.--1,715 sq mi.

Gage.--Nonrecording gage ~une 1915 to September 1936 and December 1938 to June 1939; recording gage thereafter. Datum .of gage is 733.36 ft above mean sea level, datum of 1929, Parkersburg­ Uniontown supplementary adjustment of 1944. Stage-discharge relation.--Defined by current-meter measurements below 77,000 cfs and extended to 100,000 cfs on basis of slope-area method. Remarks.--Regulation since July 1943 by Youghiogheny River Reservoir and since 1925 by Deep Creek Reservoir (combined capacity, 352,770 acre-ft). Annual. peak discharges not materially affected by regulation. Records from June 1915 to September 1929, June 1931 to September 1936, and December 1938 to September 1941 in reports of Pennsylvania Department of Forests and Waters. Records from November 1890 to June 1915 and October 1929 to June 1931 computed on basis of comparison with Weather Bureau records for West Newton about 2 miles upstream.

Annual flood stages and discharges Discharge Discharge 'Date (cfs) Date (cfs)

1891, Feb. 17------21.1 ------52,200 1918, Feb. 20------18.73 ------42,600 1892, Jan. 14------15 .. 9 ------32,800 1919, Jan. 2------16.2 ------33,800 1893, Feb. 11------13.8 ------26,000 1919, Nov. 27------17.0 ------36,500 1894, Feb. 10------11.7 ------19,700 1921, Mar. 3------12.8 ------23,000 1895, Jan. 8------16.~ ------36,200 1921, Nov. 29------19.1 ------·44, 200 1896, July 25------20.0 ------· _4 7,800 1923, Feb. 14------11.4 ------18,900 1897, Feb. 23------24.2 ------64,800 1924, Mar. 30------27.5 ------78,900. 1898, Mar. 22------13.8 ------26,00() 1925, Feb. 8------12.26 ------21,500 1899, May 18------16.9 ------36,200 1926, Feb. 23------12.5 ------22,100 1900, Feb. 9-----.--- 11.3 ------18,600 1927, Jan. 22------14.50 ------28,200 1901, Apr. 7------16.6 ------35,100 1927, Oct. 20------18.50 ------41,9.00 1902, Mar. 1------23.2 ------60,600 1929, Feb. 27------12.17 ------21,200 1903, Mar. 1------17.3 ------37,600 1929, Oct. 3------16.9 ------36,200 1904, ~an. 22------44,000 1931, Apr. 5------12.7 ------22,700 1905, Mar. 21------16.0 ------33,100 1932, Apr. 1------15.3 ------30,800 1906, Jan. 23------15.9 ------32,800 1933, Mar. 14------21.06 ------52,200 1907, Mar. 14------30.E ------100,000 1934, Mar. 4------23.0 ------31,000 1908, Feb. 15------20.8 ------51,000 1935, Jan. 22------15.3 ------30,800 1909, Feb. 24------13.1 ------23,900 1936, Mar. 18------30.65 ------100,000 1910, Jan. 19------17.4 ------37,900 1937, Apr. 26------22.8 ------·59 ,000 1911, Jan. 30------18.0 ------40,000 1937, Oct. 29------20.3 ------49,000 1912, Mar. 21------· ------69,100 1939, Feb. 4------18.5 ------41,900 1913, Jan. 8------18.7 ------42,600 1940, Mar. 31------18.40 ------41,500 1914, Mar. 16------17.8 ------~- 39,300 1941, June 5------27.34 ------78,000 1915, Feb. 2------17.9 ------39,600 1942, Apr. 10------14.46 ------28,200 1916, Mar. 23------20.5 ------49,800 1917 Jan. 22------20.5 ------49,800 20 FLOODS IN PENNSYLVANIA AND MARYLAND

(12) Casselman River at Markleton, Pa.

1 11 11 Location.--Lat 39°51 35 , long. 79°13 1 40 , at highway bridge at Markleton, Somerset County, 2 miles southwest of Casselman and 7 miles downstream from Coxes Creek. Drainage area.--382 sq mi. Gage.--Nonrecording gage August 1913 to November 1940 and recording gage thereafter. Datum of ---gage is 1,655.29 ft above mean sea level, adjustment of 1907.

Stag~-discharge relation.--Defined by current-meter measurements below 13,000 cfs and extended to 36,000 cfs by slope-area .method. Remarks.--Slight diversions above station to borough of Salisbury, Pa., and to city of Frostburg, Md., do not materially aff~ annual peak discharges. Records August 1913 to September 1941 in reports of Pennsylvania Department of Forests and Waters. Records for station at Confluence not used because of severe backwater effect at flood stages. Fragmentary records prior to 1915.

Annual flood stages and discharges Gage Discharge Gage Discharge Date height (cfs) Date height (cfs) (feet) (feet) 1915, Jan. 7------8.5 ------11' 900 1933, Mar. 14------9.8 ------15,700 1916, Mar. 22------8.9 ------13,100 1934, Aug. 16------· 8.7 ------12,500 1917, Jan. 22------10.0 ------16,200 1935, Jan. 22------7.6 ------9,350 1918, Feb. 26------9.7 ------15,400 1936, Mar. 17------16.4 ------35,800 1919, Jan. 2------7.5 ------9,070 1937, Apr. 26------12 .8· ------24,600 1920, Mar. 12------8.4 ------11,600 1937' Oct. 28------10.0 ------16,200 1921, Mar. 3------7.5 ·------9,070 1939, Feb. 3------8.7 ------12,500 1921, Nov. 28------7.55 ------9,350 1940, Mar. 31------7.8 ------9,910 1923, Feb. 2------6.6 ------6,650 1941, Jtine 5------10.24 ------18,700 1924, Mar. 29------12.17 ------· 22,800 1942, Mar. 9------7.35 ------9,330 1925, Feb. 12------6.5 ------6,400 1942, Dec. 30------8.42 ------12,500 1926, Jan. 19------7.5 ------9,070 1944, May 7------6.77 ------7,620 1927, Jan. 5------7.4 ------8,790 1945, Feb. 27------8.63 ------13,200 1928, Apr. 30------10.00 ------1"6, 200 1946, June 2------7.24 ------8,740 1929, Feb. 26------7.0 ------7,700 1947, July 31------·6.98 ------8,170 1929, Oct. 3------7.6 ------9,350 1948, Apr. 13------8.16 ------11,800 1931, Apr. 4------7.4. ------8,790 1949, Jan. 26------7.23 ------8,740 1932, Apr. 1------7.2 ------8,240 1950, Mar. 28-----'-- 7.55 ------9,940

(13) Big Piney Run near Salisbury, Pa.

Location.--Lat 39°43'32", long. 79°02'57", an eighth of a mile upstream from Little Piney Run, a quarter of a mile north of Maryland-Pennsylvania State line, and 2! miles southeast of Salis­ bury, Somerset County. Drainage area.--24.5 sq mi. Gage.--Recording gage. Stage-discharge relation.--Defined by current-meter measurements below 500 cfs and extended to 4,300 cfs on basis of slope-area determination at 4,100 cfs.

Annual flood stages and discharges Gage Discharge Gage Discharge Date height {cfs) Date height (cfs) (feet) (feet) 1933, Mar. 14-----.. -- 6.1 ------1,900 1942, May 16------4.67 ------1,290 1934, Jan. 7------5.1 ------968 1943, Oct. 15------6.21 ------3,460 1935, Feb. 15------4.05 ------494 1944, May 7------3.88 ------· 628 1936, Mar. 17 ------· 7.5 ------4,100 1945, Feb. 27------4.42 ------1,050 1937, Apr. 26------7.6 ·------4,300 1946, June 19------4.26 ------908 1937, Oct. 28------6.04 ------1,860 1947, Mar. 14------3.89 ------634 1939, Jan. 31------· 5.28 ------1,180 1948, Jan. 1------· 4.2~ ------876 1940, Aug. 27------5.69 ------1,510 1949, Jan. 26------3.62 ------472 1941, June 4------5.38 ------1,260 1950, Mar. 27------4.12 ------796 YOUGHIOGHENY RIVER BASIN 21

(14) Laurel Hill Creek at Ursina, Pa.

11 Location.--Lat 39°49 115", long. 79°19 1 15 , at Ursina, Somerset County, 500 .ft downstream .from bridge on State Highway 53 and 2.7 miles upstream .from mouth. Drainage area.--121 sq mi. Gage. -·-Nonrecording gage .from August 1913 to July 1939 and recording gage therea.fter. Datum o.f recording gage 1,335.26 .ft above mean sea level, unadjusted. Datum o.f nonrecording gage, at site 0.7_miles downstream, 1,329.06 .ft above mean sea level. Stage-discharge relation.--Prior to July 1939, de.fined by current-meter measurements below 4,600 c.fs, and extended to 11,000 c.fs on basis o.f slope-area determination; therea.fter, de.fined by current-meter measurements below 5,400 c.fs and extended to 9,400 c.fs. Remarks.--Slight regulation at low .flow by mills upstream. Records .from August 1913 to September 1941 in re~orts o.f Pennsylvania Department o.f Forests and Waters. Records .for station at Con.fluence not uSed because o.f severe backwater e.f.fect at .flood stages.

Annual .flood stages and discharges Gage Discharge Gage Discharge Date height ( c.fs) Date heigh) (c.fs) (.feet) (.feet 1914, June 28------6.20 ------3,220 1933, Mar. 14------7.5 ------4,860 1915, Jan. 7------6.99 ------4,140 1934, Aug. 16------6.6 ------·3, 660 1916,. Mar. 22.------8.0· ------5,630 1935, Aug. 2------6.86· ------. 4,020 1917, Jan. 22-----.;..- 8.2 ------· 5,970 1936, Mar. 17------10.28 ------10,300 1918, Feb. 20------8.0 ------5,630 1937, Apr. 26------7.5 ·------4,860 1919, Jan. 2------6 .. 1 ------3,110 1937, Oct. 28------7.6 ------5,010 1920, June 17------7.2 ------4,410 1_939, Feb. 3------7.58 ·------~- 5,010 1921, Jan. 23------6.1 ------3,110 Change in site and datum 1921, Dec. 24------6.31 ------3,330 1940, Mar. 30------6.28 ·------·6,510 1923, July 11------5.1 ------2,070 1941, June 4------7.98 ------9,400 1924, Mar. 29------9.30 ------8,090 1942, Apr. 9------4.57 ------3,580 1925, Feb. 9------7.9 ------4,300 1942, Dec. 30------5.81 ------·5,660 1925, Oct. 25------6.66 ------3,780 1944, Apr. 23------4.24 ------3,100 1927, Jan. 21------8.0------5,630 1945, Mar. 6------5.96· ------6,000 1927, Oct. 19------8.20 ------5;970 1946, June 2------5.12 ------4,470 1929, June 28------5.15 ------2,170 1947, July 31------5.91 ------·5 ,830 19Z9, Oct. 3------· 7.10 ------4,2'70 1948, Apr. 13------. 5.4a ------5,150 1931, Apr. 4------5.76 ------2,780 1949, Aug. 18------5.20 ------4,360 1932, Mar. 31---·----· 5.45 ------2,370 1950, Apr. 24------4.31 ------2,900 22 FLOODS IN PENNSLYVANIA AND MARYLAND

(15) Green Lick Run at Green Lick Reservoir, Pa.

11 Location.--Lat 40°06'20", long. 79°30 1 05 , at upstream errd of Green Lick Reservoir, Fayette County, 1.3 miles upstream from Latter Run, and 3! miles southeast of Mount Pleasant. Drainage area.--3.07 sq mi. Gage.--Recording gage. Stage-discharge relation.--Defined by current-meter measurements below 150 cfs and extended to 550 cfs by logarithmic plotting. Discharges for flood crests affected by backwater determined by slope-area·method. Remarks.--Records prior to August 1941 furnished by Municipal Authority of Westmoreland County. Records prior to 1929 incomplete; gage placed in operation-about 1915.

Annual flood stages and discharges Discharge Discharge Date (cfs) Date (cfs)

1929, Feb. 26------2.21 ------126 1940, Mar. 30------2.73 ------282 1929, Oct. 2 .... ------2.69 ------266 1941, June 4------3.20 ------520 1931·, May 7------2.77 ------298 1942, Mar. 9------2.72 ------·---- 278 1932, Mar. 31------2.32 ------153 1943, Aug. 13------5.1 ------1,400 1933, Mar. 13------2.67 ------260 1944, May 24------5.42 ------590 1934, Mar. 3------2.44 ------186. 1945, Mar. 6------2.54 ------216 1935, Aug. 2------2.85 ------332 1946, July 1------3.24 ------546 1936, Mar. 17------3.18 ------508 1947, June 7------2.70 ------270 1937, Apr. 25------2.46 ------191 1948, Apr. 12------2.40 ------174 1938, July 18------3.21 ------526 1949, Aug. 18------2.66 ------256 1939, Feb. 3------2.40 ------174 1950, Jan. 6------2.43 ------183

INT--PUP. SEC., WASH. • D.C. 27096